Rock Tumbler Doubles As Ice Cream Maker

When working with limited space or even with limited funding, finding a tool that can do many things for less space or cost than its separate counterparts is a tempting option. The most common downside is that these tools often can’t perform as well as the single-purpose tools they replace, with the obvious example being a pocket-sized multitool or Swiss Army knife. Even things like combination drill and driver tools, adjustable crescent wrenches, or even a kitchen stand mixer can’t quite perform as well as their dedicated counterparts. So when we find a tool that can do two things equally well, like this rock tumbler that can also make a delicious bowl of ice cream, it’s definitely noteworthy.

The project comes to us by way of [North_Stordeur] whose main goal was to create a delicious bowl of ice cream but was deterred by the cost of purpose-built ice cream makers. Making ice cream isn’t a particularly complex process, though, and [North_Stordeur ] realized that grinding down ice for ice cream shares similarities with tumbling and polishing rocks. Normally, the rocks to be polished are placed in a drum with grit and a liquid, then the drum is placed on the tumbler and spun, which causes the rocks to bounce around inside the drum with the grit and smooth out relatively quickly. Replacing sugar for grit, ice for rocks, and milk for the liquid, the ice eventually is worn all the way down, creating an excellent bowl of ice cream.

Truly, the only downside we could see with a build like this is that the drum in the National Geographic rock tumbler that [North_Stordeur] chose for this project looks like it would only make a single serving at a time. However, with picky eaters around who like their own additions to ice cream, this might be a perk as everyone can make exactly the style they like with their own choice of flavors. It’s an excellent discovery for anyone already grinding and polishing rocks or someone who has already built a DIY ball mill for any number of other uses.

13 thoughts on “Rock Tumbler Doubles As Ice Cream Maker

  1. I’d love to see some experimentation with a heavy agitator or two added to the internal container to aerate the mix as it goes. Ice cream is roughly 50% air by design – the reason for the paddles in a traditional ice cream maker – and a closed container in a rock tumbler won’t get you there. You’ll get a sweet, tasty, and mostly-frozen treat (that I wouldn’t turn down if offered) but it’s a lot closer to a gelato.

      1. How about liquid nitrogen – “aerates” and freezes as it vaporizes? You can find all kinds of stuff on YouTube etc. about it.

        Dry ice might work (and be easier to find as I’ve seen it in grocery stores now), but you’d have to consider venting the excess vapor off. If you didn’t the pressure would rise and you’d either get an explosive mess or carbonated ice cream that would fizz out of the container when you opened it.

        Now that you mention it, it sounds like a lot of fun….

  2. “grinding down ice for ice cream” yeah, that’s not how ice cream is made and not what’s going on here. The ingredients (milk, sugar etc) are in the separate inner container, the ice and salt are outside it in the tumbler and only there to make the inner container cold. There’s no grinding, it’s just melting as per usual for ice and turning into cold brine.

  3. The best way to make ice cream without any special equipment is to have a kitchen freezer, a big bowl, a rigid spoon, and patience. Simply make the ice cream base of your choice, then freeze it until fully solid. Remove from the freezer and let warm to the point of soft serve consistency. Mix it vigorously with the spoon to break up the ice crystals and whip some air into it. Cover and refreeze. Serve and enjoy.

    I’ve tried various ice cream makers over the years and I learned it’s all just more effort to clean and maintain than it’s worth. There is nothing magical or unique about purpose built equipment, everyone makes ice cream by creaming partially frozen custard. You can get the same exact effect by just freezing and partially thawing the base before creaming it.

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